No, it has never been a dayticket and many years ago when I got stranded in LOn and had to buy such a thing (could still be done at Liv.Street at the time) I was noted that due to rampant abuse by to many englishmen it had to specify the final destination on it.
Checks are the same as for normal Dutch tickets or check-ins: one has always to travel away from the point and not toward.
The RET is thus also not a rover, but you can use it to that effect in just 2 hrs-the bus to Schiedam will eat a big chunk out of that. But as such you could get on the metro, change at Beurs and go as far as den Haag on RET-metro and even forget to check out in the den Haag section as its non-gates there. It is also unknown what happens if you overstay the 2 hrs in the gated metro when you try to checkout-in buses its usually no problem to check in at 1h59 m and finish the journey (RET buses also go some 2O/25 kms away from R-dam-as far as Zoetermeer or Dordrecht.
Also from another specific discussion about this: since some time its ONLY valid on NS and not anymore on trains by other operators in NL. Of course the daytickets mentioned above are valid on all, except Thalys. Logically most people would start using the NS portion from Schiedam, where the repl.buses end for now. and which is the logical change point anyway for Amsterdam etc.